package config

import (
	"bufio"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// TestShippedExampleEnvActuallyBoots loads each example env exactly as an
// operator would and asserts the result passes validation.
//
// THIS TEST EXISTS BECAUSE BOTH EXAMPLES SHIPPED A CONFIGURATION THAT COULD NOT
// START. HTTP_WRITE_TIMEOUT was 30s in files an operator is told to copy, while
// validateWriteTimeout refuses anything at or under the deep tier's 2m
// deadline — so `cp .env.docker.example .env && docker compose up` failed at
// boot. Separately, .env.docker.example carried no model block at all, which in
// production is a second refusal for a missing MODEL_API_KEY.
//
// Neither was a subtle bug. Both survived because the examples were prose to
// every test in this package: the validator and the file documenting it had no
// mechanical connection, so tightening one silently invalidated the other.
// That connection is this test.
//
// CAVEAT: `go test` does not treat these files as inputs, so a run that changes
// ONLY an example env can be served a stale pass from the test cache. Verify
// example edits with `-count=1`. `make test` and CI run from a clean cache and
// are not affected.
func TestShippedExampleEnvActuallyBoots(t *testing.T) {
	for _, tc := range []struct {
		path string
		// Values an operator must supply, standing in for the placeholders the
		// file ships. Only credentials and hostnames belong here — anything
		// else would be this test papering over a broken example.
		operatorSupplies map[string]string
	}{
		{
			path:             filepath.Join("..", "..", "..", "infrastructure", ".env.docker.example"),
			operatorSupplies: map[string]string{"MODEL_API_KEY": "gsk-operator-supplied"},
		},
		{
			path:             filepath.Join("..", "..", "..", ".env.example"),
			operatorSupplies: map[string]string{"MODEL_API_KEY": "gsk-operator-supplied"},
		},
	} {
		t.Run(filepath.Base(tc.path), func(t *testing.T) {
			env, err := parseDotenv(tc.path)
			if err != nil {
				t.Fatalf("reading %s: %v", tc.path, err)
			}
			for k, v := range tc.operatorSupplies {
				env[k] = v
			}
			// Each file is validated under the APP_ENV IT DECLARES, not under
			// one this test imposes. The two examples describe different
			// deployments and each is internally consistent: .env.docker.example
			// is production with sslmode=require, .env.example is development
			// with sslmode=disable. Forcing production onto the development file
			// fails it on a setting that is correct for what it is.
			if env["APP_ENV"] == "" {
				t.Fatalf("%s declares no APP_ENV; every example must say what it is", tc.path)
			}

			os.Clearenv()
			for k, v := range env {
				t.Setenv(k, v)
			}

			cfg, err := Load()
			if err != nil {
				t.Fatalf("%s cannot start: %v\n\n"+
					"An operator copying this file gets this error, not a running service. "+
					"Fix the example, not this test.", tc.path, err)
			}
			// Load() succeeding is the assertion. These guard the two specific
			// regressions above, so a future edit that reintroduces either one
			// fails by name rather than as a generic validation error.
			if cfg.HTTP.WriteTimeout <= DeepestAgentDeadline {
				t.Errorf("HTTP_WRITE_TIMEOUT is %s, which does not exceed the deep tier's %s deadline",
					cfg.HTTP.WriteTimeout, DeepestAgentDeadline)
			}
			for _, m := range []struct{ key, id string }{
				{"MODEL_FAST", cfg.Model.Fast},
				{"MODEL_BALANCED", cfg.Model.Balanced},
				{"MODEL_DEEP", cfg.Model.Deep},
			} {
				if m.id == "" {
					t.Errorf("%s resolved empty", m.key)
				}
			}
		})
	}
}

// parseDotenv reads the KEY=value lines an example file ships.
//
// Deliberately simple: it handles what these files actually contain — comments,
// blank lines, trailing `# ...` notes on a value, and optional quotes. It is
// not a general dotenv implementation, and an example needing one would be an
// example too clever for the operator who has to read it.
func parseDotenv(path string) (map[string]string, error) {
	f, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	env := map[string]string{}
	scanner := bufio.NewScanner(f)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		line = strings.TrimPrefix(line, "export ")
		key, value, ok := strings.Cut(line, "=")
		if !ok {
			continue
		}
		key = strings.TrimSpace(key)
		// A trailing comment, but only when it is spaced off the value — a
		// bare # inside a password is part of the password.
		if i := strings.Index(value, " #"); i >= 0 {
			value = value[:i]
		}
		value = strings.TrimSpace(value)
		value = strings.Trim(value, `"'`)
		env[key] = value
	}
	return env, scanner.Err()
}