package docgen

import (
	"fmt"
	"strings"
)

// Sources are the files configuration is declared in.
//
// Listed rather than discovered, because "every file with a koanf tag" would
// sweep in structs that are configuration in the Go sense and not in the
// operator's — a scoring weight built at wiring time is not something anyone
// writes in a file. A test checks the list against what is actually tagged, so
// a new configuration file is a failure here rather than a silent omission.
var Sources = []string{
	"internal/config/config.go",
	"internal/agent/agent.go",
	"internal/agent/discovery/discover.go",
	"internal/agent/engines/engine.go",
	"internal/agent/engines/llamacpp.go",
	"internal/agent/engines/vllm.go",
	"internal/agent/engines/sglang.go",
	"internal/agent/engines/sim.go",
	"internal/agent/supervisor/supervisor.go",
	"internal/tlsconf/tlsconf.go",
	"internal/control/catalog/catalog.go",
	"internal/router/admission/controller.go",
	"internal/accounting/cost.go",
}

// notReference are files with koanf tags that an operator never writes.
//
// Inventory and catalog entries carry them so the same structs can be decoded
// from an API payload or a model file; putting them in a configuration
// reference would invite somebody to write them into server.yaml.
var notReference = []string{
	"internal/control/inventory/inventory.go",
}

// Render turns collected blocks into the reference document.
func Render(blocks []Block) string {
	var b strings.Builder
	b.WriteString(`# Configuration reference

Every setting llmgw reads from a file, with the type it takes and what it is
for.

**Generated from the source.** The descriptions are the comments on the fields
themselves, so this cannot describe a setting that does not exist or miss one
that does — and a test fails when it has drifted. Do not edit it; edit the
comment and run ` + "`go generate ./...`" + `.

Where a setting takes another block, the block is listed under its own heading
rather than repeated.

`)

	// An index first: the reason to open a reference is usually to find one
	// key, and scanning thirteen headings for it is the thing this replaces.
	b.WriteString("## Every key\n\n| Key | Type | In |\n|---|---|---|\n")
	for _, bl := range blocks {
		for _, f := range bl.Fields {
			b.WriteString(fmt.Sprintf("| `%s` | %s | [%s](#%s) |\n",
				f.Key, code(f.Type), bl.Name, anchor(bl.Name)))
		}
	}
	b.WriteString("\n")

	for _, bl := range blocks {
		fmt.Fprintf(&b, "## %s\n\n", bl.Name)
		if bl.Doc != "" {
			b.WriteString(bl.Doc + "\n\n")
		}
		for _, f := range bl.Fields {
			fmt.Fprintf(&b, "### `%s`\n\n%s\n\n", f.Key, code(f.Type))
			if f.Doc != "" {
				b.WriteString(f.Doc + "\n\n")
			}
			if f.Nested != "" && hasBlock(blocks, f.Nested) {
				fmt.Fprintf(&b, "Takes a [%s](#%s) block.\n\n", f.Nested, anchor(f.Nested))
			}
		}
	}
	return b.String()
}

func hasBlock(blocks []Block, name string) bool {
	for _, b := range blocks {
		if b.Name == name {
			return true
		}
	}
	return false
}

func code(s string) string { return "`" + s + "`" }

// anchor is how GitHub and Gitea slug a heading.
func anchor(s string) string { return strings.ToLower(s) }