import SwiftUI
import ProxyCore
import GRDB

struct MapLocalView: View {
    @State private var rules: [MapLocalRule] = []
    @State private var showAddRule = false
    @State private var editingRule: MapLocalRule?
    @State private var ruleToDelete: MapLocalRule?
    @State private var showDeleteConfirmation = false
    @State private var observation: AnyDatabaseCancellable?

    private let rulesRepo = RulesRepository()

    var body: some View {
        List {
            Section {
                VStack(alignment: .leading, spacing: 8) {
                    Text("Map Local")
                        .font(.headline)
                    Text("Intercept requests and replace the response with local content. Define custom mock responses for matched URLs.")
                        .font(.subheadline)
                        .foregroundStyle(.secondary)
                }
                .padding()
            }
            .listRowInsets(EdgeInsets())

            Section("Rules") {
                if rules.isEmpty {
                    EmptyStateView(
                        icon: "doc.on.doc",
                        title: "No Map Local Rules",
                        subtitle: "Tap + to create a new rule."
                    )
                } else {
                    ForEach(rules) { rule in
                        Button {
                            editingRule = rule
                        } label: {
                            VStack(alignment: .leading, spacing: 4) {
                                Text(rule.name ?? rule.urlPattern)
                                    .font(.subheadline.weight(.medium))
                                Text(rule.urlPattern)
                                    .font(.caption)
                                    .foregroundStyle(.secondary)
                                Text("Status: \(rule.responseStatus)")
                                    .font(.caption2)
                                    .foregroundStyle(.tertiary)
                            }
                        }
                        .tint(.primary)
                    }
                    .onDelete { indexSet in
                        if let index = indexSet.first {
                            ruleToDelete = rules[index]
                            showDeleteConfirmation = true
                        }
                    }
                }
            }
        }
        .navigationTitle("Map Local")
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                Button { showAddRule = true } label: {
                    Image(systemName: "plus")
                }
            }
        }
        .sheet(isPresented: $showAddRule) {
            AddMapLocalRuleSheet(rulesRepo: rulesRepo, isPresented: $showAddRule)
        }
        .sheet(item: $editingRule) { rule in
            AddMapLocalRuleSheet(rulesRepo: rulesRepo, existingRule: rule, isPresented: .constant(true))
        }
        .confirmationDialog("Delete this rule?", isPresented: $showDeleteConfirmation, presenting: ruleToDelete) { rule in
            Button("Delete", role: .destructive) {
                if let id = rule.id {
                    try? rulesRepo.deleteMapLocalRule(id: id)
                }
            }
        }
        .task {
            observation = rulesRepo.observeMapLocalRules()
                .start(in: DatabaseManager.shared.dbPool) { error in
                    print("Map Local observation error: \(error)")
                } onChange: { newRules in
                    rules = newRules
                }
        }
    }
}

// MARK: - Add Map Local Rule Sheet

private struct AddMapLocalRuleSheet: View {
    let rulesRepo: RulesRepository
    let existingRule: MapLocalRule?
    @Binding var isPresented: Bool
    @Environment(\.dismiss) private var dismiss

    @State private var name = ""
    @State private var urlPattern = ""
    @State private var method = "ANY"
    @State private var responseStatus = "200"
    @State private var responseHeadersJSON = ""
    @State private var responseBody = ""
    @State private var contentType = "application/json"

    private var methods: [String] { ["ANY"] + ProxyConstants.httpMethods }

    init(rulesRepo: RulesRepository, existingRule: MapLocalRule? = nil, isPresented: Binding<Bool>) {
        self.rulesRepo = rulesRepo
        self.existingRule = existingRule
        self._isPresented = isPresented
    }

    var body: some View {
        NavigationStack {
            Form {
                Section {
                    TextField("Name (optional)", text: $name)
                    TextField("URL Pattern (e.g. */api/*)", text: $urlPattern)
                        .textInputAutocapitalization(.never)
                        .autocorrectionDisabled()
                }

                Section {
                    Picker("Method", selection: $method) {
                        ForEach(methods, id: \.self) { m in
                            Text(m).tag(m)
                        }
                    }
                }

                Section("Response") {
                    TextField("Status Code", text: $responseStatus)
                        .keyboardType(.numberPad)
                    TextField("Content Type", text: $contentType)
                        .textInputAutocapitalization(.never)
                        .autocorrectionDisabled()
                }

                Section {
                    TextEditor(text: $responseHeadersJSON)
                        .font(.system(.body, design: .monospaced))
                        .frame(minHeight: 100)
                } header: {
                    Text("Response Headers (JSON)")
                } footer: {
                    Text("Optional JSON object of headers, for example {\"Cache-Control\":\"no-store\",\"X-Mock\":\"1\"}")
                }

                Section("Response Body") {
                    TextEditor(text: $responseBody)
                        .font(.system(.body, design: .monospaced))
                        .frame(minHeight: 120)
                }

                Section {
                    Button("Save") {
                        let status = Int(responseStatus) ?? 200
                        if let existing = existingRule {
                            let updated = MapLocalRule(
                                id: existing.id,
                                name: name.isEmpty ? nil : name,
                                urlPattern: urlPattern,
                                method: method,
                                responseStatus: status,
                                responseHeaders: normalizedHeadersJSON,
                                responseBody: responseBody.isEmpty ? nil : responseBody.data(using: .utf8),
                                responseContentType: contentType.isEmpty ? nil : contentType,
                                isEnabled: existing.isEnabled,
                                createdAt: existing.createdAt
                            )
                            try? rulesRepo.updateMapLocalRule(updated)
                        } else {
                            var rule = MapLocalRule(
                                name: name.isEmpty ? nil : name,
                                urlPattern: urlPattern,
                                method: method,
                                responseStatus: status,
                                responseHeaders: normalizedHeadersJSON,
                                responseBody: responseBody.isEmpty ? nil : responseBody.data(using: .utf8),
                                responseContentType: contentType.isEmpty ? nil : contentType
                            )
                            try? rulesRepo.insertMapLocalRule(&rule)
                        }
                        isPresented = false
                        dismiss()
                    }
                    .disabled(urlPattern.isEmpty)
                }
            }
            .navigationTitle(existingRule == nil ? "New Map Local Rule" : "Edit Map Local Rule")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("Cancel") {
                        isPresented = false
                        dismiss()
                    }
                }
            }
            .onAppear {
                if let rule = existingRule {
                    name = rule.name ?? ""
                    urlPattern = rule.urlPattern
                    method = rule.method
                    responseStatus = String(rule.responseStatus)
                    if let body = rule.responseBody, let str = String(data: body, encoding: .utf8) {
                        responseBody = str
                    }
                    responseHeadersJSON = prettyPrintedHeaders(rule.responseHeaders) ?? ""
                    contentType = rule.responseContentType ?? "application/json"
                }
            }
        }
    }

    private var normalizedHeadersJSON: String? {
        let trimmed = responseHeadersJSON.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !trimmed.isEmpty else { return nil }
        guard let data = trimmed.data(using: .utf8),
              let object = try? JSONSerialization.jsonObject(with: data),
              let dict = object as? [String: String],
              let normalized = try? JSONEncoder().encode(dict),
              let json = String(data: normalized, encoding: .utf8) else {
            return nil
        }
        return json
    }

    private func prettyPrintedHeaders(_ json: String?) -> String? {
        guard let json,
              let data = json.data(using: .utf8),
              let object = try? JSONSerialization.jsonObject(with: data),
              let pretty = try? JSONSerialization.data(withJSONObject: object, options: [.prettyPrinted]),
              let string = String(data: pretty, encoding: .utf8) else {
            return json
        }
        return string
    }
}