import Foundation
import Testing
@testable import CodexBarCore

struct VeniceUsageFetcherTests {
    @Test
    func `parses DIEM balance response`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "DIEM",
          "balances": {
            "diem": 90.50,
            "usd": null
          },
          "diemEpochAllocation": 100.0
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        #expect(snapshot.canConsume == true)
        #expect(snapshot.consumptionCurrency == "DIEM")
        #expect(snapshot.diemBalance == 90.50)
        #expect(snapshot.usdBalance == nil)
        #expect(snapshot.diemEpochAllocation == 100.0)
    }

    @Test
    func `parses USD balance response`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "USD",
          "balances": {
            "diem": null,
            "usd": 25.75
          },
          "diemEpochAllocation": null
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        #expect(snapshot.canConsume == true)
        #expect(snapshot.consumptionCurrency == "USD")
        #expect(snapshot.diemBalance == nil)
        #expect(snapshot.usdBalance == 25.75)
        #expect(snapshot.diemEpochAllocation == nil)
    }

    @Test
    func `parses string-encoded balances and allocation`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "DIEM",
          "balances": {
            "diem": "90.50",
            "usd": "25.75"
          },
          "diemEpochAllocation": "100.0"
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        #expect(snapshot.diemBalance == 90.50)
        #expect(snapshot.usdBalance == 25.75)
        #expect(snapshot.diemEpochAllocation == 100.0)
    }

    @Test
    func `parses both DIEM and USD present`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "BUNDLED_CREDITS",
          "balances": {
            "diem": 50.0,
            "usd": 10.0
          },
          "diemEpochAllocation": 100.0
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        #expect(snapshot.diemBalance == 50.0)
        #expect(snapshot.usdBalance == 10.0)
    }

    @Test
    func `uses DIEM allocation progress for bundled credits currency`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "BUNDLED_CREDITS",
          "balances": {
            "diem": 50.0,
            "usd": 10.0
          },
          "diemEpochAllocation": 100.0
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.resetDescription?.contains("DIEM 50.00 / 100.00") == true)
        #expect(usage.primary?.usedPercent == 50.0)
    }

    @Test
    func `uses USD display when consumptionCurrency is USD and both balances exist`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "USD",
          "balances": {
            "diem": 50.0,
            "usd": 12.34
          },
          "diemEpochAllocation": 100.0
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.resetDescription == "$12.34 USD remaining")
        #expect(usage.primary?.usedPercent == 0)
    }

    @Test
    func `handles canConsume=false`() throws {
        let json = """
        {
          "canConsume": false,
          "consumptionCurrency": "USD",
          "balances": {
            "diem": null,
            "usd": 100.0
          },
          "diemEpochAllocation": null
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.usedPercent == 100)
        #expect(usage.primary?.resetDescription == "Balance unavailable for API calls")
    }

    @Test
    func `displays DIEM with epoch allocation`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "DIEM",
          "balances": {
            "diem": 75.0,
            "usd": null
          },
          "diemEpochAllocation": 100.0
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.resetDescription?.contains("DIEM 75.00 / 100.00") == true)
        #expect(usage.primary?.usedPercent == 25.0)
    }

    @Test
    func `displays DIEM without allocation`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "DIEM",
          "balances": {
            "diem": 50.0,
            "usd": null
          },
          "diemEpochAllocation": null
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.resetDescription?.contains("DIEM 50.00 remaining") == true)
        #expect(usage.primary?.usedPercent == 0)
    }

    @Test
    func `displays USD balance`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "USD",
          "balances": {
            "diem": null,
            "usd": 15.50
          },
          "diemEpochAllocation": null
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.resetDescription?.contains("$15.50") == true)
        #expect(usage.primary?.usedPercent == 0)
    }

    @Test
    func `handles zero balances`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "USD",
          "balances": {
            "diem": 0.0,
            "usd": 0.0
          },
          "diemEpochAllocation": null
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.resetDescription == "No Venice API balance available")
        #expect(usage.primary?.usedPercent == 100)
    }

    @Test
    func `handles null balances with canConsume=true`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": null,
          "balances": {
            "diem": null,
            "usd": null
          },
          "diemEpochAllocation": null
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.resetDescription == "No Venice API balance available")
        #expect(usage.primary?.usedPercent == 100)
    }

    @Test
    func `identity uses venice provider ID`() throws {
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "DIEM",
          "balances": {
            "diem": 90.0,
            "usd": null
          },
          "diemEpochAllocation": 100.0
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.identity?.providerID == .venice)
        #expect(usage.identity?.accountEmail == nil)
        #expect(usage.identity?.accountOrganization == nil)
    }

    @Test
    func `throws on malformed JSON`() {
        let json = "[{ \"canConsume\": true }]"
        #expect {
            _ = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        } throws: { error in
            guard case VeniceUsageError.parseFailed = error else { return false }
            return true
        }
    }

    @Test
    func `throws on invalid JSON`() {
        let json = "{ invalid json }"
        #expect {
            _ = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        } throws: { error in
            guard case VeniceUsageError.parseFailed = error else { return false }
            return true
        }
    }

    @Test
    func `clamps used percent to 0-100 range`() throws {
        // Negative used percent should be clamped to 0
        let json = """
        {
          "canConsume": true,
          "consumptionCurrency": "DIEM",
          "balances": {
            "diem": 150.0,
            "usd": null
          },
          "diemEpochAllocation": 100.0
        }
        """
        let snapshot = try VeniceUsageFetcher._parseSnapshotForTesting(Data(json.utf8))
        let usage = snapshot.toUsageSnapshot()
        #expect(usage.primary?.usedPercent == 0)
    }
}