import Foundationimport Testing@testable import CodexBarCore struct CopilotUsageModelsTests {    @Test    func `decodes quota snapshots payload`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "assigned_date": "2025-01-01",              "quota_reset_date": "2025-02-01",              "quota_snapshots": {                "premium_interactions": {                  "entitlement": 500,                  "remaining": 450,                  "percent_remaining": 90,                  "quota_id": "premium_interactions"                },                "chat": {                  "entitlement": 300,                  "remaining": 150,                  "percent_remaining": 50,                  "quota_id": "chat"                }              }            }            """)         #expect(response.copilotPlan == "free")        #expect(response.assignedDate == "2025-01-01")        #expect(response.quotaResetDate == "2025-02-01")        #expect(response.quotaSnapshots.premiumInteractions?.remaining == 450)        #expect(response.quotaSnapshots.chat?.remaining == 150)    }     @Test    func `decodes chat only quota snapshots payload`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "entitlement": 200,                  "remaining": 75,                  "percent_remaining": 37.5,                  "quota_id": "chat"                }              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat?.quotaId == "chat")        #expect(response.quotaSnapshots.chat?.entitlement == 200)        #expect(response.quotaSnapshots.chat?.remaining == 75)    }     @Test    func `preserves missing date fields as nil`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "entitlement": 200,                  "remaining": 75,                  "percent_remaining": 37.5,                  "quota_id": "chat"                }              }            }            """)         #expect(response.assignedDate == nil)        #expect(response.quotaResetDate == nil)    }     @Test    func `preserves explicit empty date fields`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "assigned_date": "",              "quota_reset_date": "",              "quota_snapshots": {                "chat": {                  "entitlement": 200,                  "remaining": 75,                  "percent_remaining": 37.5,                  "quota_id": "chat"                }              }            }            """)         #expect(response.assignedDate?.isEmpty == true)        #expect(response.quotaResetDate?.isEmpty == true)    }     @Test    func `decodes monthly and limited quota payload`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "monthly_quotas": {                "chat": "500",                "completions": 300              },              "limited_user_quotas": {                "chat": 125,                "completions": "75"              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions?.quotaId == "completions")        #expect(response.quotaSnapshots.premiumInteractions?.entitlement == 300)        #expect(response.quotaSnapshots.premiumInteractions?.remaining == 75)        #expect(response.quotaSnapshots.premiumInteractions?.percentRemaining == 25)         #expect(response.quotaSnapshots.chat?.quotaId == "chat")        #expect(response.quotaSnapshots.chat?.entitlement == 500)        #expect(response.quotaSnapshots.chat?.remaining == 125)        #expect(response.quotaSnapshots.chat?.percentRemaining == 25)    }     @Test    func `does not assume full quota when limited quotas are missing`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "monthly_quotas": {                "chat": 500,                "completions": 300              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat == nil)    }     @Test    func `computes monthly fallback per quota only when limited value exists`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "monthly_quotas": {                "chat": 500,                "completions": 300              },              "limited_user_quotas": {                "completions": 60              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions?.quotaId == "completions")        #expect(response.quotaSnapshots.premiumInteractions?.entitlement == 300)        #expect(response.quotaSnapshots.premiumInteractions?.remaining == 60)        #expect(response.quotaSnapshots.premiumInteractions?.percentRemaining == 20)        #expect(response.quotaSnapshots.chat == nil)    }     @Test    func `merges direct and monthly fallback lanes when direct is partial`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "entitlement": 200,                  "remaining": 75,                  "percent_remaining": 37.5,                  "quota_id": "chat"                }              },              "monthly_quotas": {                "chat": 500,                "completions": 300              },              "limited_user_quotas": {                "chat": 125,                "completions": 60              }            }            """)         #expect(response.quotaSnapshots.chat?.quotaId == "chat")        #expect(response.quotaSnapshots.chat?.entitlement == 200)        #expect(response.quotaSnapshots.chat?.remaining == 75)        #expect(response.quotaSnapshots.chat?.percentRemaining == 37.5)         #expect(response.quotaSnapshots.premiumInteractions?.quotaId == "completions")        #expect(response.quotaSnapshots.premiumInteractions?.entitlement == 300)        #expect(response.quotaSnapshots.premiumInteractions?.remaining == 60)        #expect(response.quotaSnapshots.premiumInteractions?.percentRemaining == 20)    }     @Test    func `decodes unknown quota snapshot keys using fallback`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "mystery_bucket": {                  "entitlement": 100,                  "remaining": 40,                  "percent_remaining": 40,                  "quota_id": "mystery_bucket"                }              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat?.quotaId == "mystery_bucket")        #expect(response.quotaSnapshots.chat?.entitlement == 100)        #expect(response.quotaSnapshots.chat?.remaining == 40)        #expect(response.quotaSnapshots.chat?.percentRemaining == 40)    }     @Test    func `ignores placeholder known snapshot when selecting unknown key fallback`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "premium_interactions": {},                "mystery_bucket": {                  "entitlement": 100,                  "remaining": 40,                  "percent_remaining": 40,                  "quota_id": "mystery_bucket"                }              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat?.quotaId == "mystery_bucket")        #expect(response.quotaSnapshots.chat?.hasPercentRemaining == true)    }     @Test    func `derives percent remaining when missing but entitlement exists`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "entitlement": 120,                  "remaining": 30,                  "quota_id": "chat"                }              }            }            """)         #expect(response.quotaSnapshots.chat?.hasPercentRemaining == true)        #expect(response.quotaSnapshots.chat?.percentRemaining == 25)    }     @Test    func `preserves over quota percent remaining`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "paid",              "quota_snapshots": {                "premium_interactions": {                  "entitlement": 500,                  "remaining": -75,                  "percent_remaining": -15,                  "quota_id": "premium_interactions"                }              }            }            """)         let snapshot = try #require(response.quotaSnapshots.premiumInteractions)        #expect(snapshot.percentRemaining == -15)        #expect(snapshot.usedPercent == 115)        #expect(snapshot.overQuotaUsedPercent == 115)        let window = try #require(CopilotUsageFetcher.makeRateWindow(from: snapshot))        #expect(window.usedPercent == 115)        #expect(window.resetDescription == "115% used")    }     @Test    func `derives over quota percent from negative remaining`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "paid",              "quota_snapshots": {                "chat": {                  "entitlement": 500,                  "remaining": -75,                  "quota_id": "chat"                }              }            }            """)         let snapshot = try #require(response.quotaSnapshots.chat)        #expect(snapshot.hasPercentRemaining)        #expect(snapshot.percentRemaining == -15)        #expect(snapshot.usedPercent == 115)        #expect(snapshot.overQuotaUsedPercent == 115)    }     @Test    func `marks percent remaining as unavailable when underdetermined`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "remaining": 30,                  "quota_id": "chat"                }              }            }            """)         #expect(response.quotaSnapshots.chat?.hasPercentRemaining == false)        #expect(response.quotaSnapshots.chat?.percentRemaining == 0)    }     @Test    func `marks percent remaining as unavailable when remaining is missing`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "entitlement": 120,                  "quota_id": "chat"                }              }            }            """)         #expect(response.quotaSnapshots.chat?.hasPercentRemaining == false)        #expect(response.quotaSnapshots.chat?.percentRemaining == 0)    }     @Test    func `falls back to monthly when direct snapshot is missing remaining`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "entitlement": 120,                  "quota_id": "chat"                }              },              "monthly_quotas": {                "chat": 400              },              "limited_user_quotas": {                "chat": 100              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat?.quotaId == "chat")        #expect(response.quotaSnapshots.chat?.entitlement == 400)        #expect(response.quotaSnapshots.chat?.remaining == 100)        #expect(response.quotaSnapshots.chat?.percentRemaining == 25)        #expect(response.quotaSnapshots.chat?.hasPercentRemaining == true)    }     @Test    func `falls back to monthly when direct snapshots lack computable percent`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "quota_snapshots": {                "chat": {                  "remaining": 30,                  "quota_id": "chat"                }              },              "monthly_quotas": {                "chat": 400              },              "limited_user_quotas": {                "chat": 100              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat?.quotaId == "chat")        #expect(response.quotaSnapshots.chat?.entitlement == 400)        #expect(response.quotaSnapshots.chat?.remaining == 100)        #expect(response.quotaSnapshots.chat?.percentRemaining == 25)        #expect(response.quotaSnapshots.chat?.hasPercentRemaining == true)    }     @Test    func `skips monthly fallback when monthly denominator is zero`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "free",              "monthly_quotas": {                "chat": 0              },              "limited_user_quotas": {                "chat": 0              }            }            """)         #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat == nil)    }     @Test    func `treats business token billing zero entitlement quotas as unavailable`() throws {        // GitHub Copilot Business token-based billing reports every quota as        // entitlement=0, remaining=0, percent_remaining=100. That previously rendered as a        // misleading "0% used" (100 - 100). A zero-entitlement quota carries no usage signal,        // so the snapshots must drop out instead of showing as usage. (#1258)        let response = try Self.decodeFixture(            """            {              "copilot_plan": "business",              "token_based_billing": true,              "quota_snapshots": {                "premium_interactions": {                  "entitlement": 0,                  "remaining": 0,                  "percent_remaining": 100,                  "quota_id": "premium_interactions"                },                "chat": {                  "entitlement": 0,                  "remaining": 0,                  "percent_remaining": 100,                  "quota_id": "chat"                },                "completions": {                  "entitlement": 0,                  "remaining": 0,                  "percent_remaining": 100,                  "quota_id": "completions"                }              }            }            """)         #expect(response.tokenBasedBilling)        #expect(response.quotaSnapshots.premiumInteractions == nil)        #expect(response.quotaSnapshots.chat == nil)    }     @Test    func `keeps unlimited chat fallback quota without percent remaining`() throws {        let response = try Self.decodeFixture(            """            {              "copilot_plan": "individual",              "quota_snapshots": {                "premium_interactions": {                  "entitlement": 200,                  "remaining": 191,                  "percent_remaining": 95.5,                  "quota_id": "premium_interactions"                },                "chat_messages": {                  "entitlement": 0,                  "remaining": 0,                  "quota_id": "chat_messages",                  "unlimited": true                }              }            }            """)

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