// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright (C) 2026 Bryan Joshua Pedini

package main

import (
	"bytes"
	"context"
	"database/sql"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"path/filepath"
	"sync"
	"testing"
	"time"

	"github.com/moby/moby/api/types/container"
)

// syncBuffer is a goroutine-safe bytes.Buffer for capturing logs and output
type syncBuffer struct {
	mu sync.Mutex
	b  bytes.Buffer
}

func (s *syncBuffer) Write(p []byte) (int, error) {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.b.Write(p)
}

func (s *syncBuffer) String() string {
	s.mu.Lock()
	defer s.mu.Unlock()
	return s.b.String()
}

// newTestLogger returns a logger writing to a captured buffer
func newTestLogger(level slog.Level) (*slog.Logger, *syncBuffer) {
	buf := &syncBuffer{}
	return NewLogger(buf, level), buf
}

// traceDiscard is a TRACE-level logger whose output is dropped (exercises every log call)
func traceDiscard() *slog.Logger {
	return NewLogger(io.Discard, LevelTrace)
}

// fakeClock returns a fixed time advancing by step on every call
type fakeClock struct {
	mu   sync.Mutex
	t    time.Time
	step time.Duration
}

func newFakeClock(start time.Time, step time.Duration) *fakeClock {
	return &fakeClock{t: start, step: step}
}

func (c *fakeClock) Now() time.Time {
	c.mu.Lock()
	defer c.mu.Unlock()
	t := c.t
	c.t = c.t.Add(c.step)
	return t
}

// seqGenerator returns the given tokens in order, then an error
func seqGenerator(values ...string) func() (string, error) {
	var mu sync.Mutex
	i := 0
	return func() (string, error) {
		mu.Lock()
		defer mu.Unlock()
		if i >= len(values) {
			return "", errors.New("generator exhausted")
		}
		v := values[i]
		i++
		return v, nil
	}
}

// testDBPath returns a fresh database path inside the test's temporary directory
func testDBPath(t *testing.T) string {
	t.Helper()
	return filepath.Join(t.TempDir(), "dpsapi.db")
}

// openTestDB opens and initializes a fresh database
func openTestDB(t *testing.T) *sql.DB {
	t.Helper()
	db, err := OpenDatabase(context.Background(), testDBPath(t), traceDiscard())
	if err != nil {
		t.Fatalf("OpenDatabase: %v", err)
	}
	t.Cleanup(func() { db.Close() })
	return db
}

// mustExec executes a statement or fails the test
func mustExec(t *testing.T, db *sql.DB, query string, args ...any) {
	t.Helper()
	if _, err := db.Exec(query, args...); err != nil {
		t.Fatalf("exec %q: %v", query, err)
	}
}

// countRows returns the number of rows in a table
func countRows(t *testing.T, db *sql.DB, table string) int {
	t.Helper()
	var n int
	if err := db.QueryRow(`SELECT COUNT(*) FROM ` + table).Scan(&n); err != nil {
		t.Fatalf("count %s: %v", table, err)
	}
	return n
}

// fakeDocker is an in-memory ContainerLister
type fakeDocker struct {
	mu         sync.Mutex
	containers []container.Summary
	err        error
	calls      int
	closed     bool
	onList     func(ctx context.Context)
}

func (f *fakeDocker) ListRunningContainers(ctx context.Context) ([]container.Summary, error) {
	f.mu.Lock()
	f.calls++
	hook := f.onList
	f.mu.Unlock()
	if hook != nil {
		hook(ctx)
	}
	f.mu.Lock()
	defer f.mu.Unlock()
	if f.err != nil {
		return nil, f.err
	}
	return f.containers, nil
}

func (f *fakeDocker) Close() error {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.closed = true
	return nil
}

func (f *fakeDocker) Calls() int {
	f.mu.Lock()
	defer f.mu.Unlock()
	return f.calls
}

// makeContainers builds n distinct container summaries
func makeContainers(n int) []container.Summary {
	out := make([]container.Summary, 0, n)
	for i := 0; i < n; i++ {
		out = append(out, container.Summary{
			ID:     fmt.Sprintf("%064x", i+1),
			Names:  []string{fmt.Sprintf("/c%d", i)},
			Image:  "busybox:latest",
			State:  container.StateRunning,
			Status: "Up 1 second",
			Labels: map[string]string{"index": fmt.Sprint(i)},
		})
	}
	return out
}

// envMap returns a lookupEnv function backed by a map
func envMap(m map[string]string) func(string) (string, bool) {
	return func(k string) (string, bool) {
		v, ok := m[k]
		return v, ok
	}
}