1use language::BufferSnapshot;
 2use std::{fmt::Write, ops::Range};
 3
 4pub fn generate_content_prompt(
 5    user_prompt: String,
 6    language_name: Option<&str>,
 7    buffer: BufferSnapshot,
 8    range: Range<usize>,
 9    project_name: Option<String>,
10) -> anyhow::Result<String> {
11    let mut prompt = String::new();
12
13    let content_type = match language_name {
14        None | Some("Markdown" | "Plain Text") => {
15            writeln!(prompt, "You are an expert engineer.")?;
16            "Text"
17        }
18        Some(language_name) => {
19            writeln!(prompt, "You are an expert {language_name} engineer.")?;
20            writeln!(
21                prompt,
22                "Your answer MUST always and only be valid {}.",
23                language_name
24            )?;
25            "Code"
26        }
27    };
28
29    if let Some(project_name) = project_name {
30        writeln!(
31            prompt,
32            "You are currently working inside the '{project_name}' project in code editor Zed."
33        )?;
34    }
35
36    // Include file content.
37    for chunk in buffer.text_for_range(0..range.start) {
38        prompt.push_str(chunk);
39    }
40
41    if range.is_empty() {
42        prompt.push_str("<|START|>");
43    } else {
44        prompt.push_str("<|START|");
45    }
46
47    for chunk in buffer.text_for_range(range.clone()) {
48        prompt.push_str(chunk);
49    }
50
51    if !range.is_empty() {
52        prompt.push_str("|END|>");
53    }
54
55    for chunk in buffer.text_for_range(range.end..buffer.len()) {
56        prompt.push_str(chunk);
57    }
58
59    prompt.push('\n');
60
61    if range.is_empty() {
62        writeln!(
63            prompt,
64            "Assume the cursor is located where the `<|START|>` span is."
65        )
66        .unwrap();
67        writeln!(
68            prompt,
69            "{content_type} can't be replaced, so assume your answer will be inserted at the cursor.",
70        )
71        .unwrap();
72        writeln!(
73            prompt,
74            "Generate {content_type} based on the users prompt: {user_prompt}",
75        )
76        .unwrap();
77    } else {
78        writeln!(prompt, "Modify the user's selected {content_type} based upon the users prompt: '{user_prompt}'").unwrap();
79        writeln!(prompt, "You must reply with only the adjusted {content_type} (within the '<|START|' and '|END|>' spans) not the entire file.").unwrap();
80        writeln!(
81            prompt,
82            "Double check that you only return code and not the '<|START|' and '|END|'> spans"
83        )
84        .unwrap();
85    }
86
87    writeln!(prompt, "Never make remarks about the output.").unwrap();
88    writeln!(
89        prompt,
90        "Do not return anything else, except the generated {content_type}."
91    )
92    .unwrap();
93
94    Ok(prompt)
95}